s = int(input())
s1 = ''
for a in s:
if (a == '(' or a == '{' or a == '<') or s1=='':
    s1 += a
elif s1!='':
    if (a==')' and s1[-1]=='(') or (a=='}' and s1[-1]=='{') or (a==']' and s1[-1]=='[') or (a=='>' and s1[-1]=='<'):
        s1=s1[:-1]
        if s1 == '':
            print('верная')
        else:
            print('неверная')